Earlier this week, Gov. Peter Shumlin boasted about progress in fixing problems on the state’s embattled health insurance website. But as lawmakers are hearing from consumer advocates and private insurers, significant hurdles remain.

In a rare appearance before the House and Senate committees on health care Tuesday, Shumlin acknowledged that the exchange has had its issues. But, he said, the insurance website is slowly but surely becoming a success story. With more than 50,000 Vermonters enrolled in exchange plans, Shumlin said Vermont has put the worst of its problems behind it.

But private insurers aren’t ready to declare victory.

“Until we see that the system is tested and the functions, you know, work, and work cleanly and efficiently, we remain unsettled with large populations moving into a system that’s not fully tested and completed,” said Kevin Goddard, vice president of external communications for BlueCross BlueShield of Vermont.

Goddard testified Thursday before the House Committee on Health Care and said that of the 54,000 Vermonters Shumlin referred to Tuesday, many are enrolled in hold-over plans that won’t exist after March.

Goddard told lawmakers that if Vermont wants to get those people into the plans being sold on the exchange, then it needs to resolve the technology issues that have so far prevented compatibility between the websites of the exchange and the websites of private insurers.

“With all that work that’s been done, the work in front of us remains very significant,” Goddard said. “In fact, there’s still a higher ground to climb, and that is that we have almost twice as many folks who are queued up to go into Vermont Health Connect in the next couple months as have gone into qualified health plans so far.”

Goddard said it’s going to take time to process that kind of volume. And he said if the information technology glitches aren’t fixed by the end of the January, then the state will need to trigger a contingency plan.

Susan Gretkowski, with the insurer MVP, seconded the need for a contingency. But she said Plan B shouldn’t involve a postponement of the exchange mandate.

Individuals and businesses with 50 or fewer employees are required to purchase their insurance through the exchange; House Republicans have said that if the website isn’t fully functional by the middle of February, then the Shumlin administration ought to defer the mandate and allow businesses to purchase plans outside the exchange.

Gretkowski, however, said the only 2014 plans for which private insurers sought rate approval last year are those sold on the exchange. And allowing businesses to continue on 2013 plans, she said, could create financial chaos for insurance companies.

In lawmakers’ first three days in Montpelier, the news rolling into legislative committee rooms about the exchange has been mostly negative. David Sickel, the deputy director of risk management at the Vermont League of Cities and Towns, said municipalities, many of which fall under the small-business mandate, have had a particularly rough go of it.

“You only get one chance to make a good first impression, and that did not happen with the launch of Vermont Health Connect,” Sickel said.

Sickel said towns will have coverage next year, in spite of, not because of, the state’s new website.

“Quite frankly, if this were a private-sector venture it would have failed because people would have taken their business elsewhere,” Sickel said.

Rep. Chris Pearson, the head of the Progressive Party caucus in Montpelier and a member of the House Committee on Health Care, said lawmakers aren’t getting a full picture of the problems from the administration.

“It’s not necessarily a cover-up,” Pearson said. “It’s just, I wish there was a higher level of frankness and just kind of a forthright presentation of the fact so that we could address the challenges together.”

Rep. Mike Fisher, the Democratic chairman of the House Committee on Health Care, said he’s going to devote weekly hearings to oversight of the exchange.

Administration officials say they’ll continue to work to fix the IT issues, but they can’t say when the problems will be solved.